Now, I'm new to the Iris thing, but reading through AR's messages, I got that feeling.
I read this, and at first it didn't seem anything out of the ordinary. That older life could be Gravemind, but the time element seemed off, but the 'outrank' part seemed extremely out of place. I know we don't know a lot about Gravemind, but I don't think that he would 'outrank' an AI (this assuming AR is an AI).An older life is here with us. He is not as helpful as I. His motives are oblique and his alliances opaque.
He plays with time even as he hides in its folds.
He outranks me and anyway, is stronger.
I can't prevail.
I will seek one of you out and leave my legacy in a small space.
Then, after AR is crumbling, he states that the unknown attacker has always been a better machine. That is when Gravemind was pushed out of the picture, and that name came from the back of my mind.
After AR is terminated, the words become poetry-like, but not in Gravemind's style of speech. Life, time, and wanting to live are all mentioned, and from what I know of Durandal, it fits the profile.
So, go through and destroy. I just simply needed to get this off my head.
And I know how Bungie like to do that.
Halo and Marathon are set in different universes.
But if the universe is destroyed and remade, and Durandal is somehow still there, then he is in the new universe.
Meh, like I said, go forth and destroy.